94 research outputs found
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Development of the Surface Urban Energy and Water balance Scheme (SUEWS) for cold climate cities
The Surface Urban Energy and Water Balance Scheme (SUEWS) is developed to include snow. The processes addressed include accumulation of snow on the different urban surface types: snow albedo and density aging, snow melting and re-freezing of meltwater. Individual model parameters are assessed and independently evaluated using long-term observations in the two cold climate cities of Helsinki and Montreal. Eddy covariance sensible and latent heat fluxes and snow depth observations are available for two sites in Montreal and one in Helsinki. Surface runoff from two catchments (24 and 45 ha) in Helsinki and snow properties (albedo and density) from two sites in Montreal are also analysed. As multiple observation sites with different land-cover characteristics are available in both cities, model development is conducted independent of evaluation.
The developed model simulates snowmelt related runoff well (within 19% and 3% for the two catchments in Helsinki when there is snow on the ground), with the springtime peak estimated correctly. However, the observed runoff peaks tend to be smoother than the simulated ones, likely due to the water holding capacity of the catchments and the missing time lag between the catchment and the observation point in the model. For all three sites the model simulates the timing of the snow accumulation and melt events well, but underestimates the total snow depth by 18–20% in Helsinki and 29–33% in Montreal. The model is able to reproduce the diurnal pattern of net radiation and turbulent fluxes of sensible and latent heat during cold snow, melting snow and snow-free periods. The largest model uncertainties are related to the timing of the melting period and the parameterization of the snowmelt. The results show that the enhanced model can simulate correctly the exchange of energy and water in cold climate cities at sites with varying surface cover
Two independent evolutionary routes to Na+/H+ cotransport function in membrane pyrophosphatases.
Membrane-bound pyrophosphatases (mPPases) hydrolyze pyrophosphate (PPi)
to transport H(+), Na(+) or both and help organisms to cope with stress
conditions, such as high salinity or limiting nutrients. Recent
elucidation of mPPase structure and identification of subfamilies that
have fully or partially switched from Na(+) to H(+) pumping have
established mPPases as versatile models for studying the principles
governing the mechanism, specificity and evolution of cation
transporters. In the present study, we constructed an accurate
phylogenetic map of the interface of Na(+)-transporting PPases
(Na(+)-PPases) and Na(+)- and H(+)-transporting PPases
(Na(+),H(+)-PPases), which guided our experimental exploration of the
variations in PPi hydrolysis and ion transport activities during
evolution. Surprisingly, we identified two mPPase lineages that
independently acquired physiologically significant Na(+) and H(+)
cotransport function. Na(+),H(+)-PPases of the first lineage transport
H(+) over an extended [Na(+)] range, but progressively lose H(+)
transport efficiency at high [Na(+)]. In contrast, H(+)-transport by
Na(+),H(+)-PPases of the second lineage is not inhibited by up to 100 mM
Na(+) With the identification of Na(+),H(+)-PPase subtypes, the mPPases
protein superfamily appears as a continuum, ranging from monospecific
Na(+) transporters to transporters with tunable levels of Na(+) and H(+)
cotransport and further to monospecific H(+) transporters. Our results
lend credence to the concept that Na(+) and H(+) are transported by
similar mechanisms, allowing the relative efficiencies of Na(+) and H(+)
transport to be modulated by minor changes in protein structure during
the course of adaptation to a changing environment. </p
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Observing crosswind over urban terrain using scintillometer and Doppler lidar
In this study, the crosswind (wind component perpendicular to a path, U-perpendicular to) is measured by a scintillometer and estimated with Doppler lidar above the urban environment of Helsinki, Finland, for 15 days. The scintillometer allows acquisition of a path-averaged value of U-perpendicular to ((U-perpendicular to) over bar), while the lidar allows acquisition of path-resolved U-perpendicular to (U-perpendicular to(x), where x is the position along the path). The goal of this study is to evaluate the performance of scintillometer estimates for conditions under which U-perpendicular to(x) is variable. Two methods are applied to estimate (U-perpendicular to) over bar from the scintillometer signal: the cumulative-spectrum method (relies on scintillation spectra) and the look-up-table method (relies on time-lagged correlation functions). The values of (U-perpendicular to) over bar of both methods compare well with the lidar estimates, with root-mean-square deviations of 0.71 and 0.73 ms(-1). This indicates that, given the data treatment applied in this study, both measurement technologies are able to obtain estimates of (U-perpendicular to) over bar in the complex urban environment. The detailed investigation of four cases indicates that the cumulative-spectrum method is less susceptible to a variable U-perpendicular to (x) /than the look-up-table method. However, the look-up-table method can be adjusted to improve its capabilities for estimating (U-perpendicular to) over bar under conditions under for which U-perpendicular to (x) is variable.Peer reviewe
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Observing wind, aerosol particles, clouds and precipitation: Finland's new ground-based remote-sensing network
The Finnish Meteorological Institute, in collaboration with the University of Helsinki, has established a new ground-based remote-sensing network in Finland. The network consists of five topographically, ecologically and climatically different sites distributed from southern to northern Finland. The main goal of the network is to monitor air pollution and boundary layer properties in near real time, with a Doppler lidar and ceilometer at each site. In addition to these operational tasks, two sites are members of the Aerosols, Clouds and Trace gases Research InfraStructure Network (ACTRIS); a Ka band cloud radar at Sodankylä will provide cloud retrievals within CloudNet, and a multi-wavelength Raman lidar, PollyXT (POrtabLe Lidar sYstem eXTended), in Kuopio provides optical and microphysical aerosol properties through EARLINET (the European Aerosol Research Lidar Network). Three C-band weather radars are located in the Helsinki metropolitan area and are deployed for operational and research applications. We performed two inter-comparison campaigns to investigate the Doppler lidar performance, compare the backscatter signal and wind profiles, and to optimize the lidar sensitivity through adjusting the telescope focus length and data-integration time to ensure sufficient signal-to-noise ratio (SNR) in low-aerosol-content environments. In terms of statistical characterization, the wind-profile comparison showed good agreement between different lidars. Initially, there was a discrepancy in the SNR and attenuated backscatter coefficient profiles which arose from an incorrectly reported telescope focus setting from one instrument, together with the need to calibrate. After diagnosing the true telescope focus length, calculating a new attenuated backscatter coefficient profile with the new telescope function and taking into account calibration, the resulting attenuated backscatter profiles all showed good agreement with each other. It was thought that harsh Finnish winters could pose problems, but, due to the built-in heating systems, low ambient temperatures had no, or only a minor, impact on the lidar operation – including scanning-head motion. However, accumulation of snow and ice on the lens has been observed, which can lead to the formation of a water/ice layer thus attenuating the signal inconsistently. Thus, care must be taken to ensure continuous snow removal
Potential Antiviral Options against SARS-CoV-2 Infection
As of June 2020, the number of people infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) continues to skyrocket, with more than 6.7 million cases worldwide. Both the World Health Organization (WHO) and United Nations (UN) has highlighted the need for better control of SARS-CoV-2 infections. However, developing novel virus-specific vaccines, monoclonal antibodies and antiviral drugs against SARS-CoV-2 can be time-consuming and costly. Convalescent sera and safe-in-man broad-spectrum antivirals (BSAAs) are readily available treatment options. Here, we developed a neutralization assay using SARS-CoV-2 strain and Vero-E6 cells. We identified the most potent sera from recovered patients for the treatment of SARS-CoV-2-infected patients. We also screened 136 safe-in-man broad-spectrum antivirals against the SARS-CoV-2 infection in Vero-E6 cells and identified nelfinavir, salinomycin, amodiaquine, obatoclax, emetine and homoharringtonine. We found that a combination of orally available virus-directed nelfinavir and host-directed amodiaquine exhibited the highest synergy. Finally, we developed a website to disseminate the knowledge on available and emerging treatments of COVID-19
Are recovery stories helpful for women with eating disorders? A pilot study and commentary on future research
Background: Anecdotally it is well known that eating disorder memoirs are popular with people with anorexia nervosa and recovery stories are readily available online. However, no research to date has empirically explored whether such stories are helpful for current sufferers. The aim of the current pilot study was to explore the efficacy of recovery narratives as a means of improving motivation and self-efficacy and to qualitatively explore patient perspectives of such stories. Method: Fifty-seven women with anorexia nervosa and subclinical anorexia nervosa participated in this online study. Participants were randomised to either receive recovery stories or to a wait-list control group. After completing baseline measures, participants read five stories about recovery, and completed post-intervention measures two weeks later. Results: The quantitative results indicated that reading stories of recovery had no effect on motivation and self-efficacy over a two-week period. In contrast, the qualitative results showed that the stories generated thoughts about the possibility of recovery and the majority indicated they would recommend them to others. Conclusions: This study adds to a growing body of research exploring the integration of voices of lived experience into treatment approaches. Future research should focus on 1) identifying for whom and at which stage of illness recovery stories might be helpful; 2) the mechanism via which they might operate; and 3) the most helpful way of presenting such stories
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Multi-scale sensible heat fluxes in the urban environment from large aperture scintillometry and eddy covariance
Sensible heat fluxes (QH) are determined using scintillometry and eddy covariance over a suburban area. Two large aperture scintillometers provide spatially integrated fluxes across path lengths of 2.8 km and 5.5 km over Swindon, UK. The shorter scintillometer path spans newly built residential areas and has an approximate source area of 2-4 km2, whilst the long path extends from the rural outskirts to the town centre and has a source area of around 5-10 km2. These large-scale heat fluxes are compared with local-scale eddy covariance measurements. Clear seasonal trends are revealed by the long duration of this dataset and variability in monthly QH is related to the meteorological conditions. At shorter time scales the response of QH to solar radiation often gives rise to close agreement between the measurements, but during times of rapidly changing cloud cover spatial differences in the net radiation (Q*) coincide with greater differences between heat fluxes. For clear days QH lags Q*, thus the ratio of QH to Q* increases throughout the day. In summer the observed energy partitioning is related to the vegetation fraction through use of a footprint model. The results demonstrate the value of scintillometry for integrating surface heterogeneity and offer improved understanding of the influence of anthropogenic materials on surface-atmosphere interactions
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